Records from the milk recording scheme of Spanish Murciano-Granadina goats were studied to estimate genetic (co)variance components and breeding values throughout the first and second lactations. The data used consisted of 49,696 monthly test-day records of milk (MY), protein (PY), fat (FY), and dry matter (DMY) yields from 5,163 goats, distributed in 20 herds, offspring of 2,086 does and 206 bucks. These records were analyzed by 2-trait random regression models (RRM) and a repeatability test-day model (RTDM). At the middle of lactation, heritability estimates for MY, DMY, and FY obtained with RTDM were larger than those estimated with RRM, and the opposite was true for PY. The RRM estimates of heritability for MY, FY, and PY were very similar throughout the trajectories of both lactations. Heritability estimates for DMY decreased through the lactation period. The genetic correlations between the first and second lactation records estimated for all traits by RRM were positive and ranged from 0.43 to 0.80 throughout the lactation curves. The correlation between BV estimated with RTDM and RRM was 0.742 for MY and 0.664 for DMY. The RRM could be a useful alternative to RTDM for the prediction of BV in this breed.

This study quantified the effects of season and photoperiodic treatment on semen and seminal plasma (SP) characteristics in 12 bucks of two Spanish goat breeds (Murciano-Granadina, and Payoya) for the past 1 year

An artificial insemination(AI) program using cooled semen was evaluated over a 7-year period in Florida goats. The effect of the following variables on pregnancy rates was analysed: production system, year and season of AI, synchronisation treatment, bucks, AI technicians, semen deposition site, days in milk at AI, milk yield and parity. Animals were reared under field conditions on commercial farms in southern Spain. Semen was collected from nine bucks and cooled at 4 degrees C until use. A total of 3,941 goats were synchronised using intravaginal progesterone sponges and inseminated 46.0 +/- 0.5 h. after sponge removal. Pregnancy was diagnosed by ultrasonography 42-46 days after AI, obtaining an average pregnancy rate of 48.7%. Logistic regression showed that production system, AI year and season, bucks and semen deposition site had a significant effect (p < 0.05) on pregnancy rate, while the other variables analysed were removed from the model. The final statistical model accounted for 59.7% of the cases analysed, suggesting that other factors not studied here may influence pregnancy rates in Florida goats.

The present study was conducted to determine the effect of different factors on pregnancy rate after artificial insemination (AI) with refrigerated and frozen semen in Payoya goats reared under commercial farm conditions. A total of 820 goats, belonging to 10 farms, was used. The total number of studied inseminations was 1384 over a 4-year period. Factors considered in the study were year, farm, month of AI, age of the goat at AI, dose of progestagen, eCG dose, buck, type of semen (refrigerated or frozen), technician, number of goats to be inseminated (group size), incidences at AI (problems, no problems, trans-cervical insemination), distance from semen collection to farm, number of previous kidding, kidding–AI interval, and milk production. The variable studied was fertility, expressed as successful kidding. Mean fertility was 59%. Six (farm, age, group size, transcervical AI, number of kidding and milk production) of the 15 factors studied presented a significant (P < 0.05) effect on fertility after AI. Our results demonstrated that it is difficult to control all the critical aspects of AI programs at the farm level. These factors should be controlled and the variations that could compromise the chance of being pregnant must be known by technicians. The good fertility results obtained during the non-breeding season emphasise the implementation of this technique so as to improve the competitiveness of the dairy Payoya breed flocks.